Core retainer for dynamoelectric machines



Aug 25, 1953 w. R. MACLAY' Er Al. 231650,31?

CORE RETAINER FOR DYNAMOELECTRIC 'MACHINES l'Filled April 12,' 1949 VII/00% INVENTORS WILLIAM R. MACLAY EM ANUEL G. SPYRIPAKIS THEIR ATTORNEY.

Patented Aug. 25, 1953 CORE RETAINER FOR DYNAMOELECTRIC MACHINES William R. Maclay and Emanuel G. Spyrdakis,

Athens, Pa., assignors to Ingersoll-Rand Company, New York, N. Y., a corporation of New Jersey Application April 12, 1949, Serial No. 86,988

(Cl. S10-258) 2 Claims.

This invention relates to retainers and more particularly to retainers for a pair of telescopically arranged members-as for example, the stator and casing members of an electric motor.

Previously, members such as those given in the example were retained against relative movement with respect to each other by such means as screws threaded through the casing into the stator or by deforming the casing into a binding relation with the stator. These arrangements have several distinct disadvantages--as for example, the structural disadvantage associated with deforming the casing, or in the former arrangement, in small compact motors there is nsuiiicient space for readily mounting the screws.

It is, accordingly, one object of this invention to retain or clamp a pair of telescopically arranged members against relative movement therebetween by exerting oppositely directed transverse forces against said members to move them in frictional engagement.

Another object of this invention is to provide a simple and effective means for exerting such force.

Other objects will become obvious from the following speciiication and accompanying drawing in which,

Figure l is a longitudinal elevation, partly in section, of an electric motor provided vwith a preierred form of the retainer,

Fig. 2 is a transverse view taken through Figure l along the line 2-2 looking in the direction of the arrows,

Fig. 3 is a view, partly form of the retainer,

Fig. 4 is a view, partly in section, of a second modification of the retainer, and

Fig. 5 is a view of the sleeve used in the second modication of the retainer.

Referring to the drawing, a preferred form of the retaining device is shown adapted, for the sake of example, to a small electric motor of the type used in hand drills and similar devices. In general, the retainer comprises means, such as the members 23 or 25, for converting a longitudinally directed force, with respect to the member, into a transverse force with respect to the motor, whereby the casing ID and stator Il of the motor are moved into engagement against relative movement with respect to each other. To this end, the said means is positioned between the stator and casing members in a notch or groove formed in and common to the adjacent opposed peripheries of the members, i. e., the inner periphery of the casing and the outer periphery of the stator. Thus, a longitudinal force exerted on said means is transmitted into oppositely directed transverse forces on the casing i0 in section, of a modified 4and stator Il whereby they are moved into and held in iirm engagement with each other against relative movement therebetween.

More specifically, the motor aforesaid includes the casing i0 in which is mounted the stator or ield structure i l encircling the rotor l2 keyed to a shaft I3 supported by bearings i I3, only one of which is shown. The bearing H3 shown is mounted in a bearing cup i4 integral with a body l5 enclosing the end of the casing it.

in order to promote air cooling of the neld structure il which includes a coil ifi and a core Il, longitudinally disposed ribs I8 are provided on the inner periphery of the casing lil thereby forming air passages H8 between the casing iii and the core H. The inner end surfaces IQ of the ribs i8 are slightly curved in order to conform with the peripheral surface of the core I1 oi generally circular or cylindrical form, as shown in Figure 2, and of slightly less diameter than the inner diameter of the casing lil, or the distance between diametrically opposed surfaces i9.

In accordance `with the practice oi the invention, the wall thickness of the casing i0 is at one portion increased somewhat to form the base 2B through which extends a pair of transverse passages 2i. The central axes of the passages 2i are substantially tangential to the inner periphery of the casing l0. Thus, the intermediate portions of the passages 2l open into the interior oi the casing ID and are exposed to the outer periphery of the core I1 whenever it is properly positioned within the casing IB. The portions of the core I1 thus exposed to the passages 2i are cut away to form the notches 22 which con form with, or form a portion of, the passages 2 i. l'n other words, when the core Il is properly aligned Within the casing i0, a passage of substantially uniform cross section throughout its entire length is formed in the easing Il! and the core Il by the cooperation of the passage 2i and the notch 22.

Positioned at intermediate portions of the passages 2i opposite the openings 2l in the passages 2l and opposite the notches 22 are distortional members 23 which, when compressed or otherwise distorted, engage the core il to force, or move, it into frictional engagement or contact with the surfaces i9 on the casing li). In the present embodiment, the distortional members 23 are shown as being plugs of the saine general cross sectional form as the passage 2! but of slightly less diameter to permit ease in inserting or removing the plug 23 from the passage 2i. `The plug 23 is shown as being made of rubber but it is to be understood that any similar type of material could be used eiectively.

Positioned within the passage 2| at the oppoa pair of rigid, or incompressible, cylindrical members, or pinsy 24, one being positioned at each end of the plug 23 in the passage 2 l. And, in furtherance to this end, the opposite ends of the passage 2l are provided with threads for the reception of socket head screws 25 which force the pins 29 into engagement with the plug 23. In practice only one of the screws 25 is rotated to compress the plug 23, the other screw 25 and pin 24 serve merely as an abutment to prevent longitudinal movement of the plug 23 along the passage 30. In this manner, the lon-A gitudinal axis of the plug 23 is shortened and the transverse axis of the plug is, accordingly, increased. Thus, the plug 23 exerts in one direction a transverse force on the periphery of the core il, and in the opposite direction a force is 'applied to the casing I0 thereby moving the core l'i into frictional engagement with the ribs i3 to firmly engage the core against movement relative to the casing I0. It is to be noted, further, that the diameter of the plug 23 yin its uncompressed state is such that the plug 23 extends into the notch 22 to assure positive engagement be tween the members so engaged even though one of the screws should back 01T and permit the distortional member to resume its natural shape.

In the alternate or modified form of the invention, shown in Figure 3, rigid members such as the balls 26 are used as means for engaging the core il. The balls 26 are of substantially less diameter than the diameter of the passage 2i thus when the pins 24 are moved inwardly, the balls 26 are forced against each other and are thereby misaligned so that at least some of the balls'are forced into the notch 22 to engage the co're I1 and'move it into frictional contact with the casing I9. The other, or remaining, balls 26 are, of course, forced into the opposite direction into Contact with'the lower portion of the passage formed in the casing i9 and exert a transverse force thereon in a direction opposite to the force exerted on the core Il'.

In this form of the invention, as in the previously described form of the invention, the engaging means, here the balls 26, are of such diameter that they extend into the notch 22 when they are resting at the bottom ofthe passage 2l thus the core Il is'engaged to the casing,y

i0 in( a positive manner even though noforce is applied to the opposite ends of the Aline of balls 23'.

Whenever it is desired to disengage the stator I I from the casing l2, the reduced portion of the passage 30 provides easy access to the pin 24 whereby the pin 24 and the plug 23 may be knocked clear of the passage 39 after the screw 25 is removed from the opposite end of the passage. By the provision of the replaceable sleeve 28, any wear or damage of the surface of the passage 39, caused for example by the imbedding of the balls 26 in the surface, or damage done to the threads provided in the passage 30 for the screw 25, does not necessitate reboring of the passage 2i and accordingly increasing, in order to obtain 'eiTective locking of the stator and casing, the size of the pins 24 and the plug 23 or the ball's29. It is merely necessary to replace the damaged sleeve 28 with a new sleeve 23.

From the foregoing description, it becomes clear that a retainer constructed in accordance with the practice of the invention accomplishes, among others, the previously said objects and is capable of engaging a pair of telescopically arranged members against relative movement therebetween in a simple yet highly effective manner."

While "we have shown and described a specific form of our invention, it is to be understood that Various changes and modications may be made without departing from the spirit of the invention as set forth in the appended claims.

We claim:

1. A retainer for an electric motorA having a stator slid'able in'a casing, comprising a transverse passage through the casing and having a portion exposed to said stator, a notch in the stator opposite said portion, balls of substantially smaller diameter than the diameter of said passage and positioned in the passage and extending into saidinotch', and means for forcing the balls against each other to move some of the balls into rm contact with the stator to force the stator into frictional engagement with the casing.

' 2. A retainer for a pair of telescopicallyarranged members, comprising a notch in the periphery'olf1 one of said members, a sleeve arranged transversely in the other said member and having an opening therein exposed to said notch,

: means into said notch and into firm engagement A second modification of the retainer is shown in Figures 4 and' 5 in which a sleeve 28fis securedr in a transverse passage 29 in the base20, and

the sleeve 28 defines a passage 30 in which are' located the pins 24 and the plug-23. The sleeve:

23 is cutaway at its intermediate'portion, as'

indicated' by 3l, thereby exposing the passage 39 to the notch22. 4The passage Yis similar also in location and other respects tothe passage 2l with the exception that one end portion of the passage'30 is reduced to a diameter somewhat less than the diameterfof the pin 24, this portion thereby acting as a stop, or abutment, for the pin 2li. Inthis form of the invention, then, the pins 24 'andthe plug 23 are inserted in the passage 39 from'on'e end thereof and a single screw 25 is provided for each passage for exerting a longitudinal force on the pin 24.

with the notch and the surface of the sleeve for moving said'members into engagement against relative movement therebetween.

WILLIAM R. MACLAY. EMANUEL G. SPYRIDAKIS.

References cited in the me of this patent UNITED sTATEs PATENTs 

